and the average Keulegati-Carpenter number is 

 "™^ '^ _ 2.1 (10) _ 7n n 



The computed value of u T/D is well beyond the range of Figure 7-84, 



and the lift coefficient should be taken to be equal to the drag coefficient 

 (for a rigid structure). Therefore, 



From equation (7-44), 



^L = Ci 1^ Dh2 k^ cos 2 0= F^^ cos 2 6 



The maximum transverse force F^ occurs when cos 26= 1.0 . Therefore, 

 F^^ = 0.7 (1025.2) (9.8) ^^^^^ ^^^2 (Q^yj^) ^ ^^74^ ^ (1,515 lb) 



where Kjj^ is found as in the preceding examples. For the example problem 

 the maximum transverse force is equal to the drag force. 



Since the inertia component of force is small (preceding example), an 

 estimate of the maximum force can be obtained by vectorially adding the drag 

 and lift forces. Since the drag and lift forces are equal and perpendicular 

 to each other, the maximum force in this case is simply 



F 



F sr -— — = * = 9 S3S N (2 144 lb") 



^max - cos 45" 0.707 '^^^ (.^.i^'* -ld; 



which occurs about when the crest passes the pile. 

 The time variation of lift force is given by 

 Fj. = 6,741 cos 2 e 



************************************* 



c c 



e. Selection of Hydrod3mamic Force Coefficients D and M . Values 

 of C/i^ , C^ and safety factors given in the sections that follow are 

 suggested values only. Selection of C^ , Cp and safety factors for a given 

 design must be dictated by the wave theory used and the purpose of the 

 structure. Values given here are intended for use with the design curves and 

 equations given in preceding sections for preliminary design and for checking 

 design calculations. More accurate calculations require the use of 

 appropriate wave tables such as those of Dean (1974) or Skjelbreia et al. 

 (1960) along with the appropriate C^ and C^ . 



7-136 



